Here are links to installation and configuration
reports for Linux laptops and notebooks featuring a 3G (GPRS, EDGE, WCDMA, UMTS, HSDPA, HSUPA) modem card
as well as for UMTS USB, PCI (mini) Express, CardBus and PCMCIA adapters. For UMTS PC-Card modems see also
the Linux PCMCIA Card Compatibility Survey.
You are welcome to
submit
your own guide, too.

Applications

umtsmon

UMTSmon(http://sourceforge.net/projects/umtsmon/)
is a tool to control and monitor a 3G (WCDMA, UMTS, HSDPA)
card in a laptop. It handles PIN codes, operator choice (roaming),
sending/receiving SMS, and the setup of the connection.

Comgt

Comgt(http://sourceforge.net/projects/comgt/)
is a command line tool for controlling, configuring and interacting with Option Wireless 3G and 2G ( HSDPA, UMTS, EDGE, GPRS, GSM) data devices within the Linux environment.

USB_ModeSwitch

USB_ModeSwitch(http://www.draisberghof.de/usb_modeswitch/)
is a mode switching tool for controlling "flip flop" (multiple device) USB gear.
Several new USB devices have their MicroSoft Windows drivers onboard; when plugged in for the first time they act like a flash storage and start installing the driver from there. After that (and on every consecutive plugging) this driver switches the mode internally, the storage device vanishes (in most cases), and a new device (like an USB modem) shows up. Some call that feature "ZeroCD". Works with e.g. Huawei E220 (aka "Vodafone EasyBox II", aka "T-Mobile wnw Box Micro") and other
UMTS devices.